AUTOMATIC AIR DUCT REGISTER
An automatic air duct register system operating within an HVAC system comprises an automatically controlled register. The register includes louvers which are electromechanically adjusted in order to control the airflow through the register. The register may be opened or closed, responsive to a programmable electronic timer or clock, an occupancy sensor, or in response to a measured temperature. The register system may be part of a control network, wherein the network communicates programming information to the register system, and wherein the network reads information from the register system. The register system may be self-powered, utilizing an electrical generator powered from airflow from the duct attached to the register system.
The present invention relates to a system comprising automatically controlled air duct registers in a heating/ventilation/air conditioning (HVAC) system.
As is well known, buildings, including homes and businesses, are typically equipped with a centrally-controlled HVAC system. A common type of HVAC system is known as a forced-air system, and comprises a central furnace (for heating) or air conditioning system (for cooling) to provide heated or cooled air, respectively, to a network of air ducts throughout the building. The air ducts deliver the heated or cooled air to various rooms within the building through registers, which are affixed to the terminus of the various ducts where they enter the rooms.
Often, HVAC systems are equipped with a single thermostat which controls the temperature in the building according to the thermostat's temperature setting. The thermostat is installed in a central location, and turns on the furnace or air conditioning system when the temperature at the thermostat falls below, or rises above, its temperature setting, indicating a need for heating or cooling, respectively.
HVAC systems with a single thermostat control are referred to as single-zoned systems. It is commonly known that the drawback to single-zoned HVAC systems is that the temperature in various rooms away from the thermostat can vary significantly from the thermostat's temperature setting, since the temperature in these rooms does not influence the thermostat to affect the cycling of the furnace or air conditioning system. The degree of air flow from the register, individual doors being open or closed, exposure to open windows, and other environment factors determine the temperature in these rooms. Thus, while the thermostat maintains the temperature of the room in which it is installed, other rooms in the building may become uncomfortably hot or cold.
Further, some rooms in the building may not be occupied for certain periods. In this case, it may be desirable to reduce the amount of heating or cooling of these rooms during these periods in order to save energy costs. In single-zoned HVAC systems, adjusting the thermostat's temperature setting can reduce the amount of heating or cooling, but affects the temperature in the entire building rather than individual rooms. If fitted with louvers that can be opened and closed mechanically, such as with lever 110 shown in
Buildings can be equipped with HVAC systems with multiple zones. Buildings with multiple-zoned HVAC systems have multiple thermostats, each controlling the temperature in a portion (zone) of the building's rooms. Each thermostat may turn on or off the airflow through the subset of ducts that service those rooms, utilizing electrically controlled in-line dampers, thus controlling heating or cooling of these areas. The thermostats may work together to control the turning on and off of the central furnace or air conditioning system, such that any thermostat indicating a need for heating or cooling may turn on the central system.
The main drawback of multiple-zoned HVAC systems is cost. The material cost of in-line dampers, power transformers used to power the dampers, control electronics, wiring, and additional thermostats can be substantial. However, the installation cost may exceed the material cost, especially if the zones are being added to an existing HVAC system; in this case, ducts must be retrofitted inside crawlspaces, walls and ceilings, and wiring routed to a controller located near the furnace or air conditioning unit. The installation work is typically done by a contractor specializing in HVAC work, resulting in high skilled labor costs.
SUMMARY OF THE INVENTIONThe invention disclosed is an automatic air duct register system (“register system”) operating within an HVAC system, comprising an automatically controlled register. The register includes louvers which are electromechanically adjusted in order to control the airflow through the register.
In one embodiment, the register may be opened or closed, responsive to an electronic timer or clock included within the register system. The timer or clock may be programmed, so that the register is closed at certain predetermined times. Thus, energy is saved, as the room is effectively cut off from the HVAC system when the register is closed. The airflow from the central furnace or air conditioning system that had been intended for this room may service other rooms within the building or home.
In another embodiment, the register may be opened or closed, responsive to an occupancy sensor determining when the room serviced by the register system is unoccupied. Thus, energy is saved, as the room is effectively cut off from the HVAC system when the register is closed. The airflow from the central furnace or air conditioning system that had been intended for this room may service other rooms within the building or home.
In another embodiment, the register system may include an infrared temperature sensor, designed to accurately measure the temperature in a room, the register's airflow controlled in accordance with the comparison of a measured temperature and a desired temperature setpoint. Thus, the temperature of the room is locally controlled with the register system, reducing temperature fluctuations and increasing comfort.
In another embodiment, the register system is part of a control network, wherein the network communicates with the register system. The register system accepts commands to set the timer or clock, or set the desired temperature setpoint. The register system may send information about the temperature measured in the room, or other information about the register system. Thus, the register system may be operated remotely with network control, obviating the need to program the register system on-site, improving the convenience of the system.
In another embodiment, the register system is self-powered, utilizing power generated from the flow of air through the register. The power may be derived utilizing a turbine connected to an electric generator. The power may be stored in a large value, low voltage capacitor (supercapacitor) or rechargeable battery, thus eliminating the need to replace batteries in the system.
The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings.
The Figures (FIG.) and the following description relate to preferred embodiments of the present invention by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of the claimed invention.
Reference will now be made to several embodiments of the present invention(s), examples of which are illustrated in the accompanying figures. Wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality. The figures depict embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein.
In one embodiment, the register may be opened and closed responsive to an electronic timer or clock included within the register system. The timer or clock may be programmed, so that the register is closed at certain predetermined times, such as during times when the room is unoccupied. Thus, energy is saved, as the room is effectively cut off from the HVAC system when the register is closed.
Control knob 211, a 24-position, single-pole detent-type switch, in conjunction with pushbutton/indicator 212, a combination 4-color LED assembly and SPST pushbutton switch, together may serve to set the clock, as well as the desired time periods during which the register is to remain closed. An operation to program the clock and these time periods may proceed as follows. The user presses pushbutton/indicator 212 until pushbutton/indicator 212 flashes yellow. The user then turns control knob 211 to the current hour of day (each detent position has a corresponding label 0-23, with 0 signifying midnight, 23 signifying 11 PM, and the numbers in between signifying the hours between midnight and 11 PM). Pressing pushbutton/indicator 212 again programs the hour of day indicated by control knob 211, setting this hour of day value as the current real-time-clock (RTC) value included in a microcontroller (described later). Next, the user presses pushbutton/indicator 212 again until pushbutton/indicator 212 flashes green. The user then turns control knob 211 to the hour of day at which it is desired that the register be opened. Pressing control knob 211 again programs this “register open” hour of day into air duct register system 201, writing this value into the RAM included in the microcontroller. Finally, the user presses pushbutton/indicator 212 again until pushbutton/indicator 212 flashes red. The user then turns control knob 211 to the hour of day at which it is desired that the register be closed. Pressing pushbutton/indicator 212 again programs this “register close” hour of day indicated by control knob 211, writing this value into the RAM included in the microcontroller. Thus, the air duct register system is programmed to open and close at the “register open” and “register close” times. As described previously, energy is saved, as the room is effectively cut off from the HVAC system when the register is closed, while saving the user from the inconvenience of manually opening and closing the register.
While one example of setting the time periods during which the register is to remain closed has been described, any number of alternative methods may be used, including those utilizing knobs, buttons, indicators, and interfaces to a personal computer such as USB.
Battery assembly 226 comprises 3 primary AA batteries connected in series and held with a plastic housing, and provides the source of power air duct register system 201. Power provided from the AA batteries in battery assembly 226 is routed to microcontroller 225. Microcontroller 225 may include an 8 bit processor, embedded RAM, embedded ROM, general purpose input/output (GPIO) lines, real-time clock (RTC), and a collection of analog-to-digital (A/D) and digital-to-analog (D/A) converters, integrated into a single IC. The ROM contained in microcontroller 225 includes basic programming code which, for example, enables the programming steps to set the timer (described previously). Microcontroller 225 also may control H-bridge MOSFET switch 227, utilizing its logic-level GPIO lines. H-bridge MOSFET switch 227 provides power to gear-reduced motor 221 derived from the AA batteries in battery assembly 226, via four switches in an H-bridge configuration. By setting the configuration of H-bridge MOSFET switch 227 using its logic-level inputs, microcontroller 225 may cause power to be applied to gear-reduced motor 220 in either a positive polarity, a negative polarity, or neither polarity (in which case power is turned off entirely). Microcontroller 225 can therefore control the gear-reduced motor 220 to rotate clockwise, counter-clockwise, or turn off, and thus control the opening or closing the ganged-together louvers 222, 223 and 224. The ROM contained in microcontroller 225 includes basic programming code which compares the programmed desired times against the current RTC value, and thus may close the louvers based on the programmed desired time periods during which the register is to remain closed, and opens the louvers at all other times.
Referring back to
As described previously, air duct register system 201 is fitted with an IR sensor (for example IC 228) which measures the room temperature. IR sensor IC 228 itself may be fitted with a lens which, through a lens opening in register grille 210 (not shown), detects IR energy reflected from a surface such as a wall. The wall may be at least 10 centimeters away from register grille 210. This reflected IR energy represents the temperature at this wall surface with reasonable accuracy. Since the temperature of the wall is a good indication of the temperature of the room, IR sensor IC 228 may in this manner measure the temperature of the room. Advantageously, measuring the temperature some distance away from the register provides a more accurate measurement of room temperature, without interference from the airflow from the register or from the temperature of the grille, as would be present in a simpler measurement or ambient temperature (for example, using a thermistor). Thus, a reflected IR temperature measurement as described improves the accuracy of the measurement of the room temperature.
While the aforementioned embodiments describe a timer and temperature control of the register, a combination of these techniques may be applied to enable a system which provides both timer and temperature control to air duct register system 201. For example, referring back to
While one example of occupancy detection is described, any other method may be used to command the opening and closing of the louvers in the register.
Air duct register system 201 may additionally be equipped with a means of determining the temperature of the air within the duct feeding the register of air duct register system 201 (duct temperature). Since the temperature of register grille 210 generally cools or warms to the duct temperature, and since microcontroller 225 is located in the direct vicinity of register grille 210, the temperature of microcontroller 225 is a reasonable approximation to the duct temperature. A diode-based temperature detector may be integrated within microcontroller 225 to effectively measure temperature of microcontroller 225, and consequently the duct temperature. A diode integrated into microcontroller 225 (not shown) may be biased with a fixed current, and the voltage drop across the diode may be converted to digital form periodically by the ADC integrated with microcontroller 225. A program contained within the ROM of microcontroller 225 may periodically compare the digitized diode voltage drop to a table of values which correlate the diode drop voltage to temperature. In this way, the temperature of microcontroller 225 can be measured, and thus a reasonable estimate of the duct temperature can be determined.
The measurement of duct temperature affords three further refinements to the described invention. First, the duct temperature (when the furnace or air-conditioning system is on) indicates whether the HVAC system is operating in “heating” or “cooling” mode. The ROM contained in microcontroller 225 may include basic programming code to determine if the duct temperature rises substantially higher than the ambient temperature (indicating the HVAC system is operating in “heating” mode), or if the duct temperature drops substantially lower than the ambient temperature (indicating the HVAC system is operating in “cooling” mode). Earlier, a method describing a programming sequence involving pushbutton/indicator 212 was used to program the system to switch between “heating” or “cooling” modes. Thus, the measurement of duct temperature removes the need for this programming step, and removes the need to reprogram the registers at seasonal changes when the HVAC system changes its mode of operation.
Second, a rapidly rising (in “heating” mode) or falling (in “cooling” mode) duct temperature indicates that the air duct is experiencing a commenced air flow from the HVAC system. On the other hand, a rapidly falling (in “heating” mode) or rising (in “cooling” mode) duct temperature indicates that the air duct is experiencing a turning off of air flow from the HVAC system. The ROM contained in microcontroller 225 may include basic programming code to periodically record the duct temperature and calculate the rate of change of the duct temperature and make this determination. Air duct register system 201 may inhibit the opening or closing of the register unless it is determined that the register is experiencing air flow from the HVAC system. Thus, advantageously, the battery life of air duct register system 201 may be extended, because fewer cycles of opening and closing of the register results, reducing the frequency of operation of gear-reduced motor 220.
While one example of the measurement of the duct temperature is described, any other method may be used to determine the duct temperature.
In one embodiment, wireless temperature thermometer/thermostat 250 provides the temperature reading across a wireless link to radio module 251. Radio module 251 may then communicate the temperature reading to microcontroller 225 in a digital format. In this embodiment, wireless temperature thermometer/thermostat 250 essentially replaces tethered temperature sensor 240 described earlier. All function and programming are otherwise identical to the system described when utilizing tethered temperature sensor 240. Wireless temperature thermometer/thermostat 250 may be thermostat manufactured by ecobee, Inc. which communicates with radio module 251. Wireless temperature thermometer/thermostat 250 has the advantage of removing the need for a wired connection to air duct register system 201, providing further freedom to place wireless temperature thermometer/thermostat 250 at a convenient location within the room. However, wireless temperature thermometer/thermostat 250 has a disadvantage of higher cost.
In another embodiment, wireless temperature thermometer/thermostat 250 controls the opening and closing of the register across a 2.4 GHz wireless link to radio module 251. Radio module 251 may then communicate the register opening and closing commands to microcontroller 225 in a digital format. In this embodiment, wireless temperature thermometer/thermostat 250 essentially provides the function of a complete thermostat function, allowing the user to program wireless temperature thermometer/thermostat 250 to set the desired temperature. Wireless temperature thermometer/thermostat 250 may be a commercially available wireless thermostat communicating via the Zigbee wireless protocol, operating in the unlicensed 2.4 GHz band, such as ecobee's smart thermostat. Radio module 251 may be the radio module associated with the wireless thermostat, also communicating with the Zigbee wireless protocol. In this embodiment, wireless temperature thermometer/thermostat 250 has the advantage of removing the need for a wired connection to air duct register system 201, and further for allowing simple remote control and programming without the user needing to access the controls on air duct register system 201 such as control knob 211 and pushbutton/indicator 212. However, in this embodiment wireless temperature thermometer/thermostat 250 has a disadvantage of still higher cost.
The wireless network may provide bidirectional communication with air duct register systems such as air duct register system 201. For example, air duct register system 201 may provide measured temperature data, battery conditions, duct “open” or “closed” status, or other information locally measured by the air duct register system. This information may be obtained when wireless node/router 411 queries air duct register system 201, based upon a request for this information from computer 410.
Thus, the register system may be operated remotely with network control, obviating the need to program the register system on-site, improving the convenience of the system.
Claims
1. An automatically adjusted air duct register system, capable of adjusting the airflow through a register in an HVAC (heating, ventilation, and air-conditioning) system, the register opened and closed responsive to an electronic timer or clock.
2. An automatically adjusted air duct register system, capable of adjusting the airflow through a register in an HVAC system, the register opened and closed responsive to an occupancy sensor; the occupancy sensor determining whether a room is occupied.
3. The system of claim 1, wherein the register is additionally opened and closed responsive to an electronic signal indicative of room temperature.
4. The system of claim 1, wherein the register is inhibited from being opened or closed, unless an indicator indicates that the air duct connected to the register has airflow.
5. The system of claim 3, wherein the register is inhibited from being opened or closed, unless an indicator indicates that the air duct connected to the register has airflow.
6. The system of claim 4, wherein the indicator that detects the airflow comprises a temperature sensor which measures the temperature within the air duct connected to the register, and indicates a change in temperature within the said air duct.
7. The system of claim 3, wherein the temperature sensor utilizes a wire-tethered temperature sensor.
8. The system of claim 3, wherein the temperature sensor utilizes a wireless temperature sensor.
9. The system of claim 5, wherein the temperature sensor utilizes a wireless temperature sensor.
10. The system of claim 3, wherein the temperature sensor utilizes an infrared sensor.
11. The system of claim 10, where the temperature sensor measures a temperature at least ten centimeters away from the duct.
12. The system of claim 5, wherein the temperature sensor utilizes an infrared sensor.
13. The system of claim 12, where the temperature sensor measures a temperature at least ten centimeters away from the duct.
14. An automatically adjusted air duct register system, capable of adjusting the airflow through a register in an HVAC system, where the power to adjust the register is derived from the flow of air through the register.
15. The system of claim 14, wherein power to adjust register is specifically derived from electric generator placed in the path of the register airflow.
16. The system of claim 14, the register opened and closed responsive to an electronic timer or clock.
17. The system of claim 14, the register opened and closed responsive to an electronic signal indicative of room temperature.
18. The system of claim 16, wherein the register is additionally opened and closed responsive to an electronic signal indicative of room temperature.
19. An automatically adjusted air duct register system, capable of adjusting the airflow through a register in an HVAC system, the register opened and closed responsive to the room temperature, the room temperature indicated by infrared sensor.
20. The system of claim 19, where the infrared sensor measures temperature at least 10 centimeters away from the duct's air flow.
21. The system of claim 19, wherein the register is inhibited from being opened or closed, unless an indicator indicates that the air duct connected to the register has airflow.
22. The system of claim 1, where a wireless network system includes a node which permits a remote adjustment of the timer or clock.
23. The system of claim 3, where a wireless network system includes a node which permits a remote adjustment of at least one of the timer or clock, or the temperature setting.
24. The system of claim 19, where a wireless network system includes a node which permits a remote adjustment of the temperature setting.
25. The system of claim 19, where a wireless network system includes a node which permits a reading of the indicated room temperature.
Type: Application
Filed: Feb 18, 2010
Publication Date: Aug 18, 2011
Inventor: Hans Dropmann
Application Number: 12/708,490
International Classification: F24F 7/00 (20060101);